Two Dimensions of Conflict: How Ideologues Imposed Ideology on Congress

Abstract

Most interpretations of ideal point estimates such as nominate scores treat the revealed space as an ideological space. This paper projects the ideal points of ideological pundits into the same estimated space and find evidence that the space is jointly generated by ideology and some other force, orthogonal to ideology as it is defined by the pundits. This second force is most likely party, although it probably includes other forces as well. On the grounds that ideology may be influencing party leaders to adopt its divisions, and that party and ideology are more correlated today than in the 1950’s, this paper begins to disentangle which force was responsible for the increased association. Preliminary evidence suggests that ideology draws party toward itself.